Cavity blackbody radiation source

ABSTRACT

A cavity blackbody radiation source is provide. The cavity blackbody radiation source comprises a blackbody radiation cavity and a carbon nanotube composite material. The blackbody radiation cavity comprises an inner surface. The carbon nanotube composite material is located on the inner surface. The carbon nanotube composite material comprises a black lacquer and a plurality of carbon nanotubes, and the plurality of carbon nanotubes is in an upright state in the black lacquer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims all benefits accruing under 35 U.S.C. § 119 fromChina Patent Application No. 201810027426.4, filed on Jan. 11, 2018, inthe China Intellectual Property Office, the contents of which are herebyincorporated by reference. The application is also related to copendingapplications entitled, “CAVITY BLACKBODY RADIATION SOURCE AND METHOD OFMAKING THE SAME”, filed on Nov. 21, 2018 (application Ser. No.16/198,549). The application is also related to copending applicationsentitled, “PLANE SOURCE BLACKBODY”, filed on Nov. 21, 2018 (applicationSer. No. 16/198,577). The application is also related to copendingapplications entitled, “CAVITY BLACKBODY RADIATION SOURCE AND METHOD OFMAKING THE SAME”, filed on Nov. 21, 2018 (application Ser. No.16/198,590). The application is also related to copending applicationsentitled, “CAVITY BLACKBODY RADIATION SOURCE AND METHOD OF MAKING THESAME”, filed on Nov. 21, 2018 (application Ser. No. 16/198,598). Theapplication is also related to copending applications entitled, “PLANESOURCE BLACKBODY”, filed on Nov. 21, 2018 (application Ser. No.16/198,606). The application is also related to copending applicationsentitled, “PLANE SOURCE BLACKBODY”, filed on Jan. 10, 2019 (applicationSer. No. 16/244,449). The application is also related to copendingapplications entitled, “BLACKBODY RADIATION SOURCE”, filed on Jan. 10,2019 (application Ser. No. 16/244,455). The application is also relatedto copending applications entitled, “BLACKBODY RADIATION SOURCE”, filedon Jan. 10, 2019 (application Ser. No. 16/244,468). The application isalso related to copending applications entitled, “BLACKBODY RADIATIONSOURCE”, filed on Jan. 10, 2019 (application Ser. No. 16/244,474). Theapplication is also related to copending applications entitled,“BLACKBODY RADIATION SOURCE”, filed on Jan. 10, 2019 (application Ser.No. 16/244,481). The application is also related to copendingapplications entitled, “PLANE SOURCE BLACKBODY”, filed on Jan. 10, 2019(application Ser. No. 16/244,488).

FIELD

The present disclosure relates to a cavity blackbody radiation source.

BACKGROUND

With a rapid development of infrared remote sensing technology, theinfrared remote sensing technology is widely used in military andcivilian fields, such as earth exploration, weather forecasting, andenvironmental monitoring. However, all infrared detectors need to becalibrated by a blackbody before they can be used. The higher anemissivity of the blackbody, the higher an accuracy of a calibration ofthe infrared detector. An effective emissivity of a cavity blackbodymainly depends on an opening size of the cavity blackbody, a shape ofthe cavity blackbody, an emissivity of a material inside the cavityblackbody, and an isothermal degree in the cavity blackbody. Therefore,selecting high emissivity intracavity surface materials has a greatsignificance for obtaining high performance blackbody radiation sources.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present technology will now be described, by wayof example only, with reference to the attached figures, wherein:

FIG. 1 is a section structure diagram of one embodiment of a cavityblackbody radiation source.

FIG. 2 is a section structure diagram of one embodiment of a cavityblackbody radiation source.

FIG. 3 is a section structure diagram of one embodiment of a cavityblackbody radiation source.

FIG. 4 is a section structure diagram of one embodiment of a cavityblackbody radiation source.

DETAILED DESCRIPTION

The disclosure is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that referencesto “another,” “an”, or “one” embodiment in this disclosure are notnecessarily to the same embodiment, and such references mean “at leastone.”

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements. Inaddition, numerous specific details are set forth in order to provide athorough understanding of the embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein can be practiced without these specificdetails. In other instances, methods, procedures, and components havenot been described in detail so as not to obscure the related relevantfeature being described. Also, the description is not to be consideredas limiting the scope of the embodiments described herein. The drawingsare not necessarily to scale, and the proportions of certain parts havebeen exaggerated to better illustrate details and features of thepresent disclosure.

Several definitions that apply throughout this disclosure will now bepresented.

The term “substantially” is defined to be essentially conforming to theparticular dimension, shape, or other feature which is described, suchthat the component need not be exactly or strictly conforming to such afeature. The term “comprise,” when utilized, means “include, but notnecessarily limited to”; it specifically indicates open-ended inclusionor membership in the so-described combination, group, series, and thelike.

The disclosure is described in relation to a cavity blackbody radiationsource. The cavity black body radiation source comprises a blackbodyradiation cavity. The blackbody radiation cavity comprises an innersurface, and a carbon nanotube composite material located on the innersurface. The carbon nanotube composite material comprises a blacklacquer and a plurality of carbon nanotubes. The plurality of carbonnanotubes is dispersed in the black lacquer. The black lacquer has highemissivity, such as PYROMARK 1200 black lacquer having an emissivity0.92, NEXTEL VELVET 811-21 black lacquer having an emissivity 0.95. Amass ratio of the plurality of carbon nanotubes in the carbon nanotubecomposite material ranges from about 1% to about 50%. In one embodiment,the mass ratio of the plurality of carbon nanotubes in the carbonnanotube composite material ranges from about 2% to about 10%.

The blackbody radiation cavity is made of a material resistant to hightemperature and having a high emissivity. The blackbody radiation cavitycan be made of hard aluminum material, aluminum alloy material oroxygen-free copper. The blackbody radiation cavity comprises a blackbodycavity and a blackbody cavity bottom. The blackbody cavity and theblackbody cavity bottom can be an integral structure. The blackbodycavity and the blackbody cavity bottom can also be two independentstructures, and the blackbody cavity bottom can be pressed into or canbe screwed into the blackbody cavity from an end opening of theblackbody cavity.

The blackbody cavity comprises a room. A cross section of the room canbe circle, ellipse, triangle, quad, or other polygon. A shape of abottom surface of the room is not limited. The shape of the bottomsurface of the room can be a flat surface, a tapered surface, aprismatic surface, or other surfaces.

In one embodiment, the plurality of carbon nanotubes is in an uprightstate in the black lacquer, and the axial directions of the plurality ofcarbon nanotube are substantially perpendicular to the inner surface ofthe blackbody radiation cavity.

In one embodiment, the cavity blackbody radiation source furthercomprises a heating element. In one embodiment, the heating elementcomprises a carbon nanotube structure.

FIG. 1 shows one embodiment in relation to a cavity blackbody radiationsource 10. The cavity black body radiation source 10 comprises ablackbody radiation cavity 101. The blackbody radiation cavity 101comprises an inner surface 102. A carbon nanotube composite material 103is located on the inner surface 102. The carbon nanotube compositematerial 103 comprises a black lacquer 104 and a plurality of carbonnanotubes 105. The plurality of carbon nanotubes 105 is dispersed andrandomly arranged in the black lacquer 104. The black lacquer 104 isPYROMARK 1200 black lacquer 104. A mass ratio of the plurality of carbonnanotubes 105 in the carbon nanotube composite material 103 is 2%.

The blackbody radiation cavity 101 is an integral cylindrical structure.A material of the blackbody radiation cavity 101 is an aluminum alloy.The blackbody cavity 101 comprises a room 104. The cavity 108 iscylindrical. A bottom surface of the cavity 108 is a flat surface.

The carbon nanotube composite material 103 is a layered structure havinga flat surface and a large surface roughness.

The cavity blackbody radiation source 10 comprises a heating element.The heating element comprises a carbon nanotube structure, a firstelectrode and a second electrode, the first electrode and the secondelectrode are located on a surface of the carbon nanotube structure andspaced apart from each other. The carbon nanotube structure is wrappedor wound around an outer surface of the blackbody radiation cavity 101.The carbon nanotube structure comprises at least one carbon nanotubefilm or at least one carbon nanotube wire. The carbon nanotube structurecomprises a plurality of carbon nanotubes joined end to end and arrangedin a preferred orientation. The plurality of carbon nanotubes of thecarbon nanotube structure extends from the first electrode to the secondelectrode.

Because the carbon nanotube structure is wrapped or wound around theouter surface of the blackbody radiation cavity 101, after the carbonnanotube structure is energized by the first electrode and the secondelectrode, the carbon nanotube structure can heat the whole blackbodyradiation cavity 101. So that a temperature field inside the blackbodyradiation cavity 101 is evenly distributed, the temperature stabilityand uniformity of the cavity blackbody radiation source 10 can beimproved. Since carbon nanotube has small density and light weight,using the carbon nanotube structure as the heating element allows thecavity blackbody radiation source 10 to have a lighter weight. Sincecarbon nanotubes have high electrothermal conversion efficiency and lowthermal resistance, and the carbon nanotube structure has smallresistance; using the carbon nanotube structure to heat the blackbodyradiation cavity has the characteristics of rapid temperature rise,small thermal hysteresis and fast heat exchange rate. Carbon nanotubeshave good toughness, and thus the cavity blackbody radiation sourcesusing the carbon nanotube structures heating element have a long servicelife.

One embodiment is described in relation to a method of making the cavityblackbody radiation source 10. The method comprises:

-   -   block (B11), providing a blackbody radiation cavity and a carbon        nanotube slurry, the blackbody radiation cavity comprises an        inner surface, and the carbon nanotube slurry comprises a black        lacquer and a plurality of carbon nanotubes;    -   block (B12), coating the carbon nanotube slurry on the inner        surface, and drying the carbon nanotube slurry to carbon        nanotube composite material.

In block (B11), providing a blackbody radiation cavity 101, theblackbody radiation cavity 101 is an integrally cylindrical structure. Amaterial of the blackbody radiation cavity 101 is an aluminum alloy. Theblackbody cavity 101 comprises a room 108. The cavity 108 iscylindrical. A bottom surface of the cavity 108 is a flat surface.

The carbon nanotube slurry comprises a black lacquer and a plurality ofcarbon nanotubes. The plurality of carbon nanotubes is dispersed andrandomly arranged in the black lacquer. The black lacquer is PYROMARK1200 black lacquer. A mass ratio of the plurality of carbon nanotubes inthe carbon nanotube composite material is 2%.

In block (B12), in the carbon nanotube composite material, the pluralityof carbon nanotubes is uniformly dispersed in the black lacquer.

In one embodiment, the method further comprises putting the heatingelement on the outer surface of the blackbody radiation cavity 101, andthe blackbody radiation cavity 101 can be heated in real time.

FIG. 2 shows one embodiment in relation to a cavity blackbody radiationsource 20. A structure of the cavity black body radiation source 20 issubstantially the same as that of the cavity black body radiation source10. The cavity blackbody radiation source 20 comprises a blackbodyradiation cavity 201. The blackbody radiation cavity 201 comprises aroom 208. The blackbody radiation cavity 201 comprises an inner surface202. A carbon nanotube composite material 203 is located on the innersurface 202. The carbon nanotube composite material 203 comprises ablack lacquer 204 and a plurality of carbon nanotubes 205. The pluralityof carbon nanotubes 205 remain in an upright state in the black lacquer204, and the axial directions of the plurality of carbon nanotube 205are substantially perpendicular to the inner surface of the blackbodyradiation cavity 201.

The plurality of carbon nanotubes 205 remain in the upright state in theblack lacquer 204, adjacent carbon nanotubes 205 are nearly parallel andform a gap. When light rays are incident on the black body radiationcavity 201, the light rays are reflected back and forth by the adjacentcarbon nanotubes 205 in the gap, and the light rays emitted from theblack body radiation cavity 201 are greatly reduced, so an emissivity ofthe carbon nanotube composite material 203 is further improved.

In one embodiment, the plurality of carbon nanotubes 205 remains in theupright state in the black lacquer 204 by a first method. The firstmethod comprises bonding an adhesive tape to a surface of the carbonnanotube composite material 203; heating the adhesive tape at a certaintemperature to make the plurality of carbon nanotubes 205 are stuck bythe tape; removing the tape at the certain temperature to pull up theplurality of carbon nanotubes 205, and make the plurality of carbonnanotubes 205 erect and substantially perpendicular to the inner surfaceof the blackbody radiation cavity 201.

In one embodiment, the plurality of carbon nanotubes 205 remains in theupright state in the black lacquer 204 by a second method. The secondmethod comprises pouring liquid glue onto a surface of the carbonnanotube composite material 203 and flowing flat the liquid glue on thesurface of the CNT composite; curing the liquid glue, and a method ofcuring depends on a nature of the liquid glue; and removing the curedliquid glue on the surface of the carbon nanotube composite material 203to make the plurality of carbon nanotubes 205 erect and substantiallyperpendicular to the inner surface of the blackbody radiation cavity201. The cured liquid glue can be removed by tweezers or other tools.

FIG. 3 shows one embodiment in relation to a cavity blackbody radiationsource 30. The cavity black body radiation source 30 comprises ablackbody radiation cavity 301. The blackbody radiation cavity 301comprises a room 308. The blackbody radiation cavity 301 comprises aninner surface 302. A carbon nanotube composite material 303 is locatedon the inner surface 302. The carbon nanotube composite material 303comprises a black lacquer 304 and a plurality of carbon nanotubes 305.The plurality of carbon nanotubes 305 is dispersed and randomly arrangedin the black lacquer 304. A surface of the carbon nanotube compositematerial 303 comprises a plurality of microstructures. The plurality ofmicrostructures can be a strip protrusion or a dot protrusion. Across-sectional shape of the strip protrusion comprises triangular,trapezoidal, square, and the like. A cross-sectional shape of the dotprotrusion comprises triangular, trapezoidal, square, and the like. Inone embodiment, the plurality of microstructures is a plurality of dotprotrusions, and each of the plurality of dot protrusions is atriangular pyramid. The black lacquer 304 is NEXTEL VELVET 811-21 blacklacquer, and an emissivity of the NEXTEL VELVET 811-21 black lacquer isabout 0.95. A mass ratio of the plurality of carbon nanotubes 305 in thecarbon nanotube composite material 303 is 5%.

A material of the blackbody radiation cavity 301 is an aluminum alloy.The blackbody radiation cavity 301 comprises a blackbody cavity and ablackbody cavity bottom. The blackbody cavity and the blackbody cavitybottom can also be two independent structures, and the blackbody cavitybottom is screwed into the blackbody cavity by a screw thread. A crosssection of the room 308 is a circular, and a bottom surface of the room308 is a tapered surface.

In one embodiment, the cavity blackbody radiation source 30 furthercomprises a heating element. The heating element comprises a carbonnanotube structure.

When all conditions except the internal surface area of the cavityblackbody radiation source are the same, the larger the internal surfacearea of the blackbody radiation cavity, the higher the emissivity of theblackbody radiation cavity. All conditions comprise a material of theblackbody radiation cavity, the inner surface material of the blackbodyradiation cavity, a diameter of the blackbody radiation cavity, and thelike. The surface of the carbon nanotube composite material 303comprises a plurality of microstructures, and thus the internal surfacearea of the blackbody radiation cavity 301 is increased, and further theemissivity of the cavity blackbody radiation source 30 is increased.

One embodiment is described in relation to a first method of making thecavity blackbody radiation source 30. The first method comprises:

-   -   block (B21), providing a blackbody radiation cavity and a carbon        nanotube slurry, the blackbody radiation cavity comprises an        inner surface, and the carbon nanotube slurry comprises a black        lacquer and a plurality of carbon nanotubes;    -   block (B22), coating the carbon nanotube slurry on the inner        surface, and drying the carbon nanotube slurry to form a carbon        nanotube composite material; and    -   block (B23), forming a plurality of microstructures on the        surface of the carbon nanotube composite material.

In block (B21), providing a blackbody radiation cavity 301. Theblackbody radiation cavity 301 comprises a blackbody cavity and ablackbody cavity bottom. The blackbody cavity bottom is screwed into theblackbody cavity by a screw thread. The blackbody radiation cavity 301comprises an inner surface, and the inner surface is a smooth surface.The blackbody radiation cavity 301 comprises a cylindrical room 308. Abottom surface of the cylindrical room 308 is a tapered surface.

The carbon nanotube slurry comprises a black lacquer and a plurality ofcarbon nanotubes. The plurality of carbon nanotubes is dispersed in theblack lacquer. The black lacquer 304 is NEXTEL VELVET 811-21 blacklacquer, and an emissivity of the NEXTEL VELVET 811-21 black lacquer isabout 0.95. A mass ratio of the plurality of carbon nanotubes in thecarbon nanotube slurry is 5%.

In block (B22), coating the carbon nanotube slurry on the inner surface,and drying the carbon nanotube slurry to form the carbon nanotubecomposite material. In the carbon nanotube composite material, theplurality of carbon nanotubes is uniformly dispersed in the blacklacquer.

In block (B23), the step of forming the plurality of microstructures onthe surface of the carbon nanotube composite material is performed by alaser irradiation. The laser beam spot diameter, power, and scanningspeed are determined by shape and size of the plurality ofmicrostructures. In one embodiment, providing a laser, an irradiationpath of a laser beam from the beam can be controlled by a computerprogram; irradiating the surface of the carbon nanotube compositematerial by the laser, to form a plurality of triangular pyramids on thesurface of the carbon nanotube composite material.

The first method can further comprise putting the heating element on theouter surface of the blackbody radiation cavity 301. The blackbodyradiation cavity 301 can be heated in real time.

One embodiment is described in relation to a second method of making thecavity blackbody radiation source 30. The second method comprises:

-   -   block (B31), providing a blackbody radiation cavity and a carbon        nanotube slurry, the blackbody radiation cavity comprises an        inner surface, and the inner surface comprises a plurality of        microstructures; and the carbon nanotube slurry comprises a        black lacquer and a plurality of carbon nanotubes; and    -   block (B32), coating the carbon nanotube slurry on the inner        surface, and drying the carbon nanotube slurry to form a carbon        nanotube composite material;

The block (B31) is substantially the same as the block (B31) except thatthe inner surface comprises a plurality of microstructures, theplurality of microstructures is a plurality of triangular pyramid, and anon-flat concave tapered groove is formed at a bottom end connectionbetween adjacent triangular pyramids.

In block (B32), a surface of each of the plurality of triangularpyramids is coated with the carbon nanotube slurry, but the carbonnanotube slurry does not completely cover the plurality of triangularpyramids, and a shape of each of the plurality of triangular pyramidsremains. Drying the carbon nanotube slurry to form a layer of carbonnanotube composite material on the surface of each of the plurality oftriangular pyramid. That is, a plurality of triangular pyramids isformed on a surface of the carbon nanotube composite material.

The plurality of microstructures can be a strip protrusion or a dotprotrusion. A cross-sectional shape of the strip protrusion can betriangular, trapezoidal, square, or the like. A cross-sectional shape ofthe dot protrusion can be triangular, trapezoidal, square, or the like.

FIG. 4 shows one embodiment in relation to a cavity blackbody radiationsource 40. A structure of the cavity black body radiation source 40 issubstantially the same as that of the cavity black body radiation source30. The cavity black body radiation source 40 comprises a blackbodyradiation cavity 401. The blackbody radiation cavity 401 comprises aroom 408. The blackbody radiation cavity 401 comprises an inner surface402. A carbon nanotube composite material 403 is located on the innersurface 402. The carbon nanotube composite material 403 comprises blacklacquer 404 and a plurality of carbon nanotubes 405. A surface of thecarbon nanotube composite material 43 comprises a plurality ofmicrostructures. The plurality of microstructures is a dot protrusion.The dot protrusion is a triangular pyramid. A mass ratio of theplurality of carbon nanotubes 405 in the carbon nanotube compositematerial 403 is 5%. The black lacquer 304 is NEXTEL VELVET 811-21 blacklacquer, and an emissivity of the NEXTEL VELVET 811-21 black lacquer isabout 0.95. The plurality of carbon nanotubes 405 remain in an uprightstate in the NEXTEL VELVET 811-21 black lacquer, and the axialdirections of the plurality of carbon nanotube 405 are substantiallyperpendicular to the inner surface of the blackbody radiation cavity401.

The plurality of carbon nanotubes 405 remain in the upright state in theblack lacquer 404, adjacent carbon nanotubes 405 are nearly parallel andform a gap. When light rays are incident on the black body radiationcavity the light rays are reflected back and forth by the adjacentcarbon nanotubes 405 in the gap, and the light rays emitted from theblack body radiation cavity 401 are greatly reduced, so an emissivity ofthe carbon nanotube composite material 403 is further improved.

A method of making the plurality of carbon nanotubes 405 remain in theupright state in the black lacquer 404 is the same with the method ofmaking the plurality of carbon nanotubes 205 remain in the upright statein the black lacquer 204.

The cavity blackbody radiation source in this disclosure has manyadvantages. First, carbon nanotubes are currently the darkest materialin the world, the emissivity of carbon nanotubes is 99.6%, which is farlarger than that of currently surface material of the inner wall of theblack body cavity. For example, an emissivity of the Nextel Velvet 81-21black lacquer is only 96%. Therefore, the emissivity of carbon nanotubecomposites comprising the carbon nanotubes and black lacquer is alsolarger than that of the surface material of currently inner wall of theblackbody cavity.

Second, currently, the cavity blackbody radiation source obtains alarger emissivity by using large emissivity coating material, increasinga depth of the blackbody radiation cavity and reducing the caliber.However, the cavity blackbody radiation source of this disclosure adoptsthe carbon nanotube composite material as the inner surface material ofthe blackbody radiation cavity, the depth of the blackbody radiationcavity is greatly reduced under the same effective emissivity of thecavity, and therefore, a miniaturization of the cavity blackbodyradiation source can be realized.

Third, when a plurality of carbon nanotubes remain in the upright statein the black lacquer, adjacent carbon nanotubes are nearly parallel andform a gap. When light rays are incident on the black body radiationcavity, the light rays are reflected back and forth by the adjacentcarbon nanotubes in the gap, and the light rays emitted from the blackbody radiation cavity are greatly reduced, so an emissivity of thecarbon nanotube composite material is further improved.

Fourth, the carbon nanotubes can be prepared by a chemical vapordeposition of carbon source gas under high temperature conditions, andthe raw materials are cheap and easy to obtain.

Fifth, the carbon nanotubes have excellent mechanical properties. Theuse of carbon nanotube materials to prepare cavity blackbody radiationsources can increase the stability of the cavity blackbody radiationsource, and make the star borne blackbody not easy to damage in harshenvironments.

It is to be understood that the above-described embodiments are intendedto illustrate rather than limit the present disclosure. Variations maybe made to the embodiments without departing from the spirit of thepresent disclosure as claimed. Elements associated with any of the aboveembodiments are envisioned to be associated with any other embodiments.The above-described embodiments illustrate the scope of the presentdisclosure but do not restrict the scope of the present disclosure.

Depending on the embodiment, certain of the steps of a method describedmay be removed, others may be added, and the sequence of steps may bealtered. The description and the claims drawn to a method may includesome indication in reference to certain steps. However, the indicationused is only to be viewed for identification purposes and not as asuggestion as to an order for the steps.

What is claimed is:
 1. A cavity blackbody radiation source comprising: ablackbody radiation cavity comprising an inner surface; and a carbonnanotube composite material located on and directly contacting the innersurface, wherein the carbon nanotube composite material consists of ablack lacquer and a plurality of carbon nanotubes dispersed in andimmersed in the black lacquer, and the plurality of carbon nanotubes isin an upright state in the black lacquer; and a surface of the carbonnanotube composite material which directly contacts the inner surface isdefined as a first surface, a surface of the carbon nanotube compositematerial away from the inner surface is defined as a second surface, thesecond surface is opposite to the first surface, and the second surfacecomprises a plurality of microstructures.
 2. The cavity blackbodyradiation source of claim 1, wherein an axial direction of each of theplurality of carbon nanotube is substantially perpendicular to the innersurface.
 3. The cavity blackbody radiation source of claim 1, wherein ashape of each of the plurality of microstructures is a strip protrusionor a dot protrusion.
 4. The cavity blackbody radiation source of claim3, wherein a cross-sectional shape of the strip protrusion istriangular, trapezoidal, or square.
 5. The cavity blackbody radiationsource of claim 3, wherein a cross-sectional shape of the dot protrusionis triangular, trapezoidal, or square.
 6. The cavity blackbody radiationsource of claim 1, wherein a mass ratio of the plurality of carbonnanotubes in the carbon nanotube composite material ranges from about 1%to about 50%.
 7. The cavity blackbody radiation source of claim 6,wherein the mass ratio of the plurality of carbon nanotubes in thecarbon nanotube composite material ranges from about 2% to about 10%. 8.The cavity blackbody radiation source of claim 1, wherein the blackbodyradiation cavity comprises an outer surface, and the cavity blackbodyradiation source comprises a heating element located on the outersurface of the blackbody radiation cavity.
 9. The cavity blackbodyradiation source of claim 8, wherein the heating element comprises acarbon nanotube structure, a first electrode and a second electrode, thefirst electrode and the second electrode are located on a surface of thecarbon nanotube structure and spaced apart from each other.
 10. Thecavity blackbody radiation source of claim 9, wherein the carbonnanotube structure comprises a plurality of carbon nanotubes joined endto end and arranged in a preferred orientation, and the plurality ofcarbon nanotubes of the carbon nanotube structure extends from the firstelectrode to the second electrode.
 11. The cavity blackbody radiationsource of claim 1, wherein the blackbody cavity defines a room.
 12. Thecavity blackbody radiation source of claim 11, wherein the room has abottom surface, and the bottom surface of the room is a flat surface, atapered surface, or a prismatic surface.
 13. The cavity blackbodyradiation source of claim 1, wherein a material of the blackbodyradiation cavity is a hard aluminum, an aluminum alloy or an oxygen-freecopper.
 14. The cavity blackbody radiation source of claim 1, whereinthe blackbody radiation cavity comprises a blackbody cavity and ablackbody cavity bottom.
 15. The cavity blackbody radiation source ofclaim 14, wherein the blackbody cavity and the blackbody cavity bottomis an integral structure.
 16. The cavity blackbody radiation source ofclaim 14, wherein the blackbody cavity comprises an end opening, and theblackbody cavity bottom is pressed into or screwed into the blackbodycavity from the end opening of the blackbody cavity.
 17. A cavityblackbody radiation source consisting of: a blackbody radiation cavitydefining an inner surface; and a carbon nanotube composite materiallocated on and directly contacting the inner surface, wherein the carbonnanotube composite material consists of a black lacquer and a pluralityof carbon nanotubes dispersed in and immersed in the black lacquer, andthe plurality of carbon nanotubes is in an upright state in the blacklacquer; and a surface of the carbon nanotube composite material whichdirectly contacts the inner surface is defined as a first surface, asurface of the carbon nanotube composite material away from the innersurface is defined as a second surface, the second surface is oppositeto the first surface, and the second surface comprises a plurality ofmicrostructures.